MySQL 8.0

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CREATE TABLE test (line GEOMETRY);
INSERT INTO test VALUES 
(ST_GeomFromText('LINESTRING (1 1, 2 2, 3 1, 4 2)'));
SELECT ST_AsText(line), ST_Length(line) FROM test;


ST_AsText(line)
ST_Length(line)


LINESTRING(1 1,2 2,3 1,4 2)
4.242640687119286